This invention relates to blanking systems, and in particular, to a method and apparatus for attaching a presser plate or a presser board mounting adapter to a presser.
In the manufacture of cartons, small sheets of paper material having specific profiles are cut out of larger sheets of paper material. These smaller sheets are known as carton blanks which, in turn, are formed into cartons and/or boxes. The blanks are formed during a process known as a blanking operation in a die cutting machine.
In a die cutting machine, the blanks are cut, but not removed from a large sheet of paper material. After the blanks have been cut, the sheet is moved downstream in the die cutting machine to a blanking station where the sheet is positioned over a frame for support. The frame includes large openings which correspond in size, in shape and in position to the profile of the carton blank previously cut. Below the frame is a mechanism for stacking the carton blanks.
At the blanking station, an upper tool is used in combination with the lower tool or frame to knock the carton blanks from the sheet of paper material while holding the scrap material that surrounds the blanks. The upper tool has a support board that moves vertically up and down in the die cutting machine, and the support board typically has a plurality of stand-offs depending therefrom that hold pushers spaced beneath the board which in turn are used to push the carton blanks from the sheet through the lower tool or frame. A plurality of presser assemblies are also mounted in the support board and depend therefrom to hold the scrap material against the lower tool or frame during the blanking operation so that the blanks may be pushed from the sheet. A presser assembly typically includes a presser rail which is biased downwardly away from the support board by a spring so that the rail is positioned slightly below the pushers. A presser plate is attached to the rail. As the upper tool is lowered, the presser plate engages the sheet of paper material first such that a scrap portion of the large sheet of material is secured against the frame. The upper tool then continues to be lowered such that the pushers engage the carton blanks and knock the blanks out of the sheet of material. The carton blank then falls into a stacking mechanism below the frame where the blanks are stacked for further processing.
Conventionally, the presser plate is attached to the rail using a pair of fasteners, e.g., screws. Accordingly, the presser plate has a pair of openings that must be aligned with corresponding openings formed in the bottom surface of the rail. Once aligned, the presser plate can be screwed to the rail. While effective in securing the plate to the rail, such a mounting system is labor intensive. Moreover, since a blanking station will typically have several presser assemblies, it can be quite time consuming to fasten a plate to each rail. And, since many blanking stations are used with different blanking processes that require different presser plates, the time consuming efforts in removing and replacing the existing presser plates can result in significant downtime of the blanking station and/or die cutting machine.